1. When did you acquire this property? To qualify for the homeowners' exemption, the home must have been the principal residence of the owner as of January 1 of that tax year.To claim the exemption, the homeowner must make a one-time filing with the county assessor where the property is located. Many California families are forgetting to claim a common homeowner tax break. Page form can get you your discount. San Mateo County residents may request a Homeowner Exemption claim form from this website. Click "Add Another" when filling out the exemption information to input information for another tax year. Do not file any exemption applications with the NYS Department of Taxation and Finance or with the Office of Real Property Tax Services. Phone: (408) 299-5500. Homeowners' Exemption Forms ; DocuSign.